JLabel l1 = new JLabel("要查找的文件路径 :"); 
		JTextField tx1 = new JTextField(...);
		JLabel l2 = new JLabel("要查找的文件内容 :"); 
		JTextField tx2 = new JTextField(...);
		JButton b = new JButton("开始查找文件");

// 使用swing来完成这个功能
		b.addActionListener(new ActionListener() {
			@Override
			public void actionPerformed(ActionEvent e) {
				SwingWorker<Void, Void> worker = new SwingWorker<Void, Void>(){

					@Override
					protected Void doInBackground() throws Exception {
						// 长耗时任务
						System.out.println("执行这个SwingWorker的线程是: " + Thread.currentThread().getName());
						b.setText("正在搜索");
						try {
							Thread.sleep(300);
							// 目标目录下
							File ff = new File(tx1.getText());
							// 要找的文件数初始值为0
							int flc = 0;
							String message = "总共找到满足条件的文件：" + String.valueOf(search(ff, tx2.getText(), flc)) + "个";
							JOptionPane.showMessageDialog(f, message);						
						} catch (InterruptedException e1) {
							e1.printStackTrace();
						}
						b.setText("搜索完成");
						return null;
					}
				};
				worker.execute();
			}	
		});

public static int search(File folder, String search, int flc) {
		String[] s = folder.list();
		File[] fl = new File[s.length];
		for (int i = 0; i < s.length; i++) {
			fl[i] = new File(folder.getAbsoluteFile() + "/" + s[i]);
			if (fl[i].isFile() && String.valueOf(fl[i]).contains(".java")) {
				String[] s0 = read(fl[i]);
				for (int j = 0; j < s0.length; j++) 
					if(String.valueOf(s0[j]).contains(search)) {
						flc++;
					} 
			}
			if (fl[i].isDirectory()) { 
				flc = search(fl[i], search, flc); 
			}
		}
		return flc;
	}

public static String[] read(File f){...}

setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
pack();
setVisible(true);

package Swing;

import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.util.ArrayList;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JTextField;
import javax.swing.SwingWorker;

public class pratice {
	static ArrayList<File> list=new ArrayList<File>();

	public static void main(String[] args) {
		JFrame f=new JFrame();
		f.setSize(400,300);
		f.setLocation(700,300);
		f.setLayout(new FlowLayout(20,20,20));
		
		JLabel l=new JLabel("搜索文件夹目录:");
		JTextField tf=new JTextField();
		tf.setPreferredSize(new Dimension(200,30));
		tf.setText("C:\\JavaPractice\\project");
		JLabel l2=new JLabel("搜  索  关  键  字:");
		JTextField tf2=new JTextField();
		tf2.setText("dao");
		tf2.setPreferredSize(new Dimension(200,30));
		JButton b=new JButton("开始搜索");
		f.add(l);
		f.add(tf);
		f.add(l2);
		f.add(tf2);
		f.add(b);
		
		b.addActionListener(new ActionListener() {
			
			public void actionPerformed(ActionEvent e) {
				SwingWorker<Void,Void> worker=new  SwingWorker<Void,Void>(){

					@Override
					protected Void doInBackground() throws Exception {
						try {
							b.setText("正在搜索");
							b.setEnabled(false);
							searchkey(tf.getText(),tf2.getText());
							JOptionPane.showMessageDialog(f, "总共找到满足条件的文件："+list.size()+"个");
							
						} catch (Exception e2) {
							System.out.println("文件夹目录/关键字  输入有误");
						}
						list=new ArrayList<File>();
						b.setText("重新搜索");
						b.setEnabled(true);
						return null;
					}
			};
			worker.execute();
			}
		});
		
		
		
		f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		f.setVisible(true);
	}
	
	public static void searchkey(String FileFolder, String search){
        File file = new File(FileFolder);
        if(file.isDirectory()){
        	File[] fileList = file.listFiles();
            if(null != fileList){
                for(File f: fileList){
                    if(f.isDirectory()) searchkey(f.getPath(), search);
                    if(f.isFile() && f.getName().endsWith(".java")){
                        try(BufferedReader bf = new BufferedReader(new FileReader(f))){
                            String line;
                            while((line = bf.readLine()) != null){
                                if(line.contains(search)){
                                	list.add(f);
                                    System.out.println(f);
                                    break;
                                }
                            }
                        }catch (IOException e){
                            e.printStackTrace();
                        }
                    }
                }
 
            }
        }
 
    }

}

public static void main(String[] args) {
		String filename="F:\\开始";
		ArrayList<String> a=new ArrayList<>();
		
	     /////////
		JFrame f=new JFrame();
		f.setTitle("LoL");
		 
        f.setSize(400, 300);

        f.setLocation(200, 200);

        f.setLayout(null);

        JButton b = new JButton("开始查找含有package的文件");
        b.setBounds(50, 50, 280, 30);
        
        final JLabel l=new JLabel();
        ImageIcon i=new ImageIcon("F:\\1.jpg");
        l.setIcon(i);
        l.setBounds(150, 150, i.getIconWidth(), i.getIconHeight());
        
        b.addActionListener(new ActionListener() {
			

			@Override
			public void actionPerformed(ActionEvent e) {
				SwingWorker<Void,Void> worker=new SwingWorker<Void,Void>(){

					@Override
					protected Void doInBackground() throws Exception {
						System.out.println("执行这个SwingWorder的线程是：" + Thread.currentThread().getName());
						search("F:\\开始",a);
						Thread.sleep(2000); 
						System.out.println(a.size());
						return null;
					}
					
				};
				worker.execute();
				
			}
			
		});
        
        l.addMouseListener(new MouseListener() {
        	  
            // 释放鼠标
            public void mouseReleased(MouseEvent e) {
                // TODO Auto-generated method stub
  
            }
  
            // 按下鼠标
            public void mousePressed(MouseEvent e) {
                // TODO Auto-generated method stub
  
            }
  
            // 鼠标退出
            public void mouseExited(MouseEvent e) {
                // TODO Auto-generated method stub
  
            }
  
            // 鼠标进入
            public void mouseEntered(MouseEvent e) {
  
                Random r = new Random();
  
                int x = r.nextInt(f.getWidth() - l.getWidth());
                int y = r.nextInt(f.getHeight() - l.getHeight());
  
                l.setLocation(x, y);
  
            }
  
            // 按下释放组合动作为点击鼠标
            public void mouseClicked(MouseEvent e) {
                // TODO Auto-generated method stub
  
            }
        });
        
        f.addKeyListener(new KeyListener() {
            public void keyReleased(KeyEvent e) {
                if (e.getKeyCode() == 39) {
                    l.setLocation(l.getX() + 10, l.getY());}}
            public void keyPressed(KeyEvent e) {}
            public void keyTyped(KeyEvent e) {}});
        
       l.grabFocus();
        f.add(b);
        f.add(l);
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        f.setVisible(true);
	}
	
	public static void search(String filename,ArrayList<String> a) {
		File f=new File(filename);
		if(f.isFile()) {
			if(f.getName().toLowerCase().endsWith(".java"))
			try (FileReader fr=new FileReader(f);
					BufferedReader br=new BufferedReader(fr);){
				while(true) {
					String line=br.readLine();
					if(line==null) {
						break;
					}
					if(line.contains("package")) {
						System.out.println(filename.toString());
						a.add(filename);
						break;
					}
				}
			} catch (FileNotFoundException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			} catch (IOException e1) {
				// TODO Auto-generated catch block
				e1.printStackTrace();
			}
		}
		if(f.isDirectory()) {
			File[] filefolder=f.listFiles();
			for(File child:filefolder) {
				search(child.getAbsolutePath(),a);
			}
			
		}
		
	}

}